1. Field of the Invention
This invention relates to improvements in the method and apparatus for continuously forming a flexible hose from a continuous strip of plastic ribbon pre-impregnated with a suitable liquid-bonding agent by helically winding such ribbon in an overlapping edge relation, and by incorporating a continuous, pre-formed helical wire between the overlapping edges of the helically wound ribbon.
2. Description of the Prior Art
A substantial portion of the prior art is characterized by the use of single hose-forming mandrel, such as shown and illustrated by U.S. Pat. Nos. 2,707,017 (Beare et al) and 2,731,070 (Meissner).
Beare employs a single rotating and axially traveling mandrel. In order to impart such functional characteristics to a mandrel, it is obvious that rather complex and costly machinery is necessary to accomplish this purpose. Additionally, the apparatus and method of hose manufacture as taught by Beare contemplates forming the reinforcing wire helix prior to forming the body of the hose by sequentially overlapping the tape wraps. This method is undesirable because it is very difficult to control the indexing of the helically-formed, reinforcing wire as it is engaged with the tape on the mandrel.
Meissner also discloses a continuous-flexible-hose-forming method and apparatus which is characterized by the use of a single mandrel. However, Meissner envisions the use of a heated mandrel about which the tape is wrapped to form a continuous hose body. Further, the reinforcing wire element of the hose, as indicated, is pre-formed prior to engagement about the mandrel. The use of a heated mandrel and pre-formed reinforcing wire is, like in the case of Beare supra, both unnecessarily complicated and costly.
Another unique method and apparatus for continuously forming a reinforced flexible hose is disclosed in U.S. Pat. No. 3,336,172 (Hall, et al). While it appears that Hall utilizes a plurality of mandrels, each of these mandrels are stationary and do not move. Further, the method and apparatus of Hall require that the wire reinforcing element of the hose be pre-formed into a helix prior to joining it with the plastic tape which forms the hose body. Still further, the final product of the Hall apparatus as depicted in FIG. 3 is such that the tape edges are subject to separation and subsequent delamination because of the structural configuration and arrangement of the overlapping tape edges. The substantial probability of such delamination occurring is unacceptable in many applications where this type of hose is likely to be used. For example, if used as a vacuum-cleaner hose, the relatively high velocity air stream traveling over the lapped tape edges presents a shearing force which tends to produce delamination of the tape edges. In essence, the same problem is presented when the hose is used to couple the effluent discharge pipe of a recreational-vehicle, holding tank to a waste-receiving tank.
A still further device which illustrates another method and apparatus for making a hose of helically wrapped reinforcing and web components used in the prior art is the invention disclosed in U.S. Pat. No. 3,325,327 (Swan). However, it may be seen that a single mandrel is used in the apparatus disclosed in Swan. Further, the single mandrel of Swan employed a plurality of so-called "mandrel segments" which are varied during rotation of the mandrel to provide a variation in pitch of the hose components being wrapped on the mandrel. In addition, the action of these mandrel segments produces forward progression of the hose body as it is being formed, thereby moving the finished hose away from the mandrel.
It should be also noted that the reinforced hose produced by Swan's apparatus requires the use of a substantial amount of tape which is necessary to produce a plurality of laminations which is required to form the hose of Swan.
In substance, the device of Swan is complex and expensive and produces an expensive, relatively inextensible, hose product.
In order to overcome the problems and disadvantages of both the devices and methods employed in the prior art as hereinbefore described and discussed, the present invention was created.